EP1710727A1 - RFID Sende-Empfangsgerät - Google Patents

RFID Sende-Empfangsgerät Download PDF

Info

Publication number
EP1710727A1
EP1710727A1 EP05255049A EP05255049A EP1710727A1 EP 1710727 A1 EP1710727 A1 EP 1710727A1 EP 05255049 A EP05255049 A EP 05255049A EP 05255049 A EP05255049 A EP 05255049A EP 1710727 A1 EP1710727 A1 EP 1710727A1
Authority
EP
European Patent Office
Prior art keywords
circuit
local oscillation
delay
signal
transmission
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP05255049A
Other languages
English (en)
French (fr)
Other versions
EP1710727B1 (de
Inventor
Teruhisa c/o FUJITSU LIMITED Ninomiya
Yusuke c/o Fujitsu Frontech Limited Kawasaki
Osamu c/o Fujitsu Limited Kuroda
Yoshinori c/o Fujitsu Limited Tanaka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujitsu Ltd
Fujitsu Frontech Ltd
Original Assignee
Fujitsu Ltd
Fujitsu Frontech Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fujitsu Ltd, Fujitsu Frontech Ltd filed Critical Fujitsu Ltd
Publication of EP1710727A1 publication Critical patent/EP1710727A1/de
Application granted granted Critical
Publication of EP1710727B1 publication Critical patent/EP1710727B1/de
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40—Circuits
    • H04B1/50—Circuits using different frequencies for the two directions of communication
    • H04B1/52—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa
    • H04B1/525—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa with means for reducing leakage of transmitter signal into the receiver
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K17/00—Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/0008—General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
    • H04B5/40—Near-field transmission systems, e.g. inductive or capacitive transmission systems characterised by components specially adapted for near-field transmission
    • H04B5/48—Transceivers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field

Definitions

  • the present invention relates to an RFID transceiver device in an RFID system, and more particularly to an RFID transceiver device in which receiver noise is improved.
  • a carrier signal is transmitted (P1) from an interrogator constituted by an RFID transceiver device 1 to a transponder for example an IC tag 2.
  • the IC tag 2 modulates the received carrier signal with information data and sends this back to the RFID transceiver device 1 by reflection (back scattering).
  • the RFID transceiver device 1 acquires information data by demodulating the reflected (P2) signal.
  • Fig. 2 shows an example of the configuration of an RFID transceiver device.
  • This RFID transceiver device is connected to a data processing device, not shown, through an external interface I/F.
  • a control and processing circuit 10 controls a local oscillation circuit 11 to generate a local oscillation signal corresponding to each channel.
  • the local oscillation signal that is generated from the local oscillation circuit 11 is modulated and amplified in power by a transmission circuit 12 before being emitted from an antenna 16 through a duplexer 13.
  • the local oscillation signal is additionally supplied to a demodulation circuit in a reception circuit 14 and the demodulation circuit outputs information data by demodulating the reflected signal from the IC tag 2.
  • a transceiving antenna 16 as shown in Fig. 2 may be employed for the RFID transceiver device 1.
  • the RFID transceiver device 1 since, in the case where the IC tag 2 is a passive tag, the operating power (power source energy) is obtained from the electromagnetic wave transmitted by the RFID transceiver device 1, the RFID transceiver device 1 needs to have large transmission power. In contrast, since the response transmission from the IC tag 2 is performed by reflection (back scattering), its power is very weak in comparison with the power of the electromagnetic wave transmitted by the RFID transceiver device. Thus, the RFID transceiver device 1 whose communications partner is a passive IC tag needs to have high output power in order to supply power source energy to the IC tag 2 and, at the same time, must be provided with a high sensitivity reception capability , since the back-scattered signal from the passive IC tag is very weak.
  • a duplexer typically constituted by a circulator or coupler 13 is provided; however, as mentioned above, the energy of the transmission signal is large, so leakage 15 of the transmission signal is generated, of a level that depends on the degree of isolation achieved by the duplexer 13. Also, as shown in Fig. 3, apart from the component 15a that passes through the duplexer with attenuation, the leakage components of the transmission signal include a component 15b that is reflected by the power feed terminal of the antenna 16. Also, as shown in Fig.
  • the transmission and reception signal frequencies f1 and f2 are different, as they are in the case of for example a mobile telephone terminal, isolation of transmission and reception can be achieved by providing bandpass filters 12a, 14a as well as the duplexer 13.
  • bandpass filters 12a, 14a as well as the duplexer 13.
  • the frequency of transmission (carrier signal) and reception (tag reflection signal) are the same, so isolation using filters is not possible.
  • phase noise of the carrier signal appears to be detected at the output of the demodulation circuit constituting the reception circuit 14.
  • low noise amplification cannot be performed upstream of the demodulation circuit.
  • Fig. 5 is an example of a specific configuration of the transmission circuit 12 and reception circuit 14 of the RFID transceiver device 1 shown in Fig. 2.
  • Fig. 6 is a view showing the input signal of the demodulation circuit 14b constituting the reception circuit 14.
  • the input signals of the demodulation circuit 14b are the local oscillation signal 17 (Fig. 6A) from the local oscillation circuit 11 and the leakage component 15 (Fig. 6B) of the transmission signal including the component 15a that is transmitted, with attenuation, through the duplexer 13 and the reflected signal 15b from the antenna power feed terminal.
  • the output of the demodulation circuit 14b may be expressed by the expression (1).
  • g [ t ] is the input noise of the VCO of the local oscillation circuit 11
  • h [ t ] is the frequency characteristic (loop filter characteristic) of the VCO input stage.
  • Fig. 7 is a graph showing the relationship between the path time difference and the noise level (relative value). From the graph of Fig. 7, it can be understood that the detected phase noise level becomes larger as the path time difference ⁇ becomes larger and if there is no path time difference, the phase noise component is substantially cancelled out.
  • Laid-open Japanese Patent Application No. 2003-174388 may be mentioned as prior art.
  • This Laid-open Japanese Patent Application No.2003-174388 mentions that the phase noise possessed by the carrier itself that is transmitted from the interrogator and the phase noise of the PLL oscillation circuit that is involved in synchronous detection appear in the demodulation signal and adversely affect reception sensitivity.
  • the object of the invention set out in Laid-open Japanese Patent Application No. 2003-174388 referred to above is to prevent lowering of the reception sensitivity in synchronous detection by the interrogator.
  • the invention set out in Laid-open Japanese Patent Application No. 2003-174388 referred to above is an arrangement in which the phase of the local signal LO is corrected using the response signal from the tag as a reference.
  • Such a configuration is effective in systems in which there is substantially no change in the amplitude/phase of the response signal and the leakage of the transmission signal i.e. systems in which the frequency is low, at about 13.56 MHz, and in which the distance to the transponder is small; at about 30 cm.
  • an RFID transceiver device comprises: a local oscillation circuit that generates a local oscillation signal; a demodulation circuit that demodulates a reception signal using the frequency of the local oscillation signal output from the local oscillation circuit; a transmission circuit that modulates and amplifies and transmits a local oscillation signal output from the local oscillation circuit; a duplexer that supplies to a transceiving antenna the transmission signal from the transmission circuit and that branches the reception signal received by the transceiving antenna to the demodulation circuit; and, in addition, a delay circuit between the local oscillation circuit and the demodulation circuit, the amount of delay of the delay circuit being set to a magnitude corresponding to the path difference between the path of the leakage through the duplexer into the demodulation circuit, of the transmission signal output from the local oscillation circuit for transmission and the path of the direct input from the local oscillation circuit to the demodulation circuit.
  • the device further comprises a control and processing circuit that detects noise level in accordance with the output of the demodulation circuit and the control and processing circuit performs feedback control of the delay amount of the delay circuit in response to the noise level that is detected.
  • an RFID transceiver device comprises: a local oscillation circuit that generates a local oscillation signal; a demodulation circuit that demodulates a reception signal_using the frequency of the local oscillation signal output from the local oscillation circuit; a modulation circuit that modulates the local oscillation signal that is output from the local oscillation circuit; a duplexer that supplies to a transceiving antenna the transmission signal output from the modulation circuit and that branches the reception signal received by the transceiving antenna to the demodulation circuit; and, in addition, the amount of delay on the path whereby the local oscillation signal that is output from the modulation circuit is supplied to the demodulation circuit being set identical to the amount of delay on the path of the leakage of the transmission signal that is input to the demodulation circuit through the duplexer.
  • any of the above RFID transceiver devices may further comprise a transceiving antenna and a delay circuit that connects the transceiving antenna and the duplexer, the amount of delay of this delay circuit being set such that the impedance of the transceiving antenna seen from the duplexer is substantially equal to the characteristic impedance.
  • detection of the noise level in the control and processing circuit may occur in a condition in which command transmission from the transmission circuit to the tag is halted.
  • an RFID transceiver device wherein lowering of the noise level can be achieved irrespective of the distance to the tag and consequently high sensitivity reception can be achieved and wherein system stabilization can be achieved at a frequency in the UHF band or above.
  • Fig. 8 is a block diagram of a first embodiment of an RFID transceiver device according to the present invention.
  • a characteristic feature of this embodiment is the provision of a delay circuit 18 between the local oscillation circuit 11 and demodulation circuit 14b.
  • a phase difference is produced because the path of the leakage signal 15, through which the transmission signal that is transmitted through the modulation circuit 12b and power amplifier 12c from the local oscillation circuit 11 leaks from the duplexer 13 to the demodulation circuit 14b,is longer than the path of the local oscillation signal 17 that is directly supplied to the demodulation circuit 14b from the local oscillation circuit 11.
  • a characteristic feature in Fig. 8 is that the path of the leakage signal 15 is equalized by using a delay circuit 18 to provide a delay on the path of the local oscillation signal 17 that is directly supplied to the demodulation circuit 14b from the local oscillation circuit 11. In this way, as shown in Fig. 7, the same situation is produced as when the path difference is "0" and the relative noise level can thus be reduced to a minimum.
  • Fig. 9 is a block diagram of a second embodiment of an RFID transceiver device according to the present invention.
  • a characteristic feature of the second embodiment is that the circuit configuration is such that the path of the local oscillation signal 17 that is supplied from the local oscillation circuit 11 to the demodulation circuit 14b is substantially equal to the path of the leakage signal 15 from the local oscillation circuit 11 via the duplexer 13.
  • a coupling circuit 12d is provided downstream of the power amplifier 12c so as to reduce the difference with regard to the path of the local oscillation signal 17 supplied to the demodulation circuit 14b and the leakage signal 15 via the duplexer 13. Additionally, an amount of delay corresponding to the minute difference of the existing paths is adjusted by providing a trimming circuit 18 between the coupling circuit 12d and the trimming circuit 14b.
  • phase noise can be reduced since the paths of the local oscillation signal 17 supplied to the demodulation circuit 14b and of the leakage signal 15 via the duplexer 13 can be made substantially the same.
  • Fig. 10 shows a third embodiment.
  • a characteristic feature of this embodiment is that the amount of delay of the delay circuit 18 in the first embodiment of Fig. 8 can be suitably controlled in accordance with the noise level that is received and detected.
  • the output of the demodulation circuit 14b is input to an A/D converter 14d through an amplifier 14c and low-pass filter 14 to be converted to a digital signal.
  • the digital output of the A/D converter 14d is input to the control and processing circuit 10, which evaluates the noise level.
  • the control and processing circuit 10 supplies a correction amount control signal 19 depending on the noise level to the delay circuit 18 so as to provide a corresponding amount of delay. In this way it is possible to control the delay amount appropriately in accordance with the noise level.
  • the control and processing circuit 10 may be configured with the provision of a correspondence table between the correction level and correction amount control signal in order to perform such control.
  • Fig. 11 is an example of the configuration of the demodulation circuit 14b in Fig. 10.
  • Fig. 12 shows the processing flow in respect of the delay circuit 18 of the control and processing circuit 10 when the demodulation circuit of Fig. 11 is employed.
  • Fig. 13 is a view given in explanation of the delay amount control in the delay circuit 18.
  • the demodulation circuit 14b comprises a quadrature separation circuit 141 that separates the reception signal RX into a mutually orthogonal I channel signal and Q channel signal, a multiplier 142 that multiplies the I channel signal and the local oscillation signal (LO) 17 that is output from the local oscillation circuit 11, and a multiplier 143 that multiplies the Q channel signal by the local oscillation signal that is output from the local oscillation circuit 11 and the phase of which is shifted by 90 ° through the phase shifter 144.
  • LO local oscillation signal
  • step S1 when the amount of delay of the delay circuit 18 is set by performing calibration, this is performed (step S1) in a condition with transmission of commands from the RFID transmission device to the IC tag disabled.
  • the power (I 2 +Q 2 ) is thus found in a condition in which transmission of commands from the RFID transmission device to the IC tag is disabled and therefore corresponds to the noise level resulting from the path difference.
  • step S3 the delay amount ⁇ of the delay circuit 18 is increased by ⁇ ⁇ 1 (step S3).
  • the power P2 when this delay amount ⁇ is increased by ⁇ ⁇ 1 and the initial power P1 are then compared (step S5). In this power comparison, if P2 ⁇ P1 (Yes in step S5), as the path of the local oscillation signal (LO) 17 that is directly input to the demodulation circuit 14b becomes larger, its difference from the path of the leakage component that arrives via the duplexer 13 becomes smaller, indicating that the noise level becomes smaller.
  • LO local oscillation signal
  • Fig. 13 shows the relationship between this path difference and noise level.
  • Fig. 13A shows the characteristic whereby the noise level increases or decreases centered on the point corresponding to a phase difference ⁇ /2 of the path difference; in this figure, the target value for feedback control is a minimum noise level.
  • Fig. 13B represents the path difference of Fig. 13A extended in the positive and negative directions and shows the direction of control towards the target value at which the noise level is a minimum, when the amount of delay of the delay circuit 18 is controlled in a range in which the path difference is smaller than the path difference corresponding to a phase difference ⁇ /2.
  • P2 ⁇ P1 corresponds for example to the direction I of control in Fig. 13B.
  • step S5 if, in step S5, P2 > P1 (No in step S5), the delay amount ⁇ is set (step S7) in the direction such as to be reduced by an amount ⁇ ⁇ 2 ( ⁇ ⁇ ⁇ 1).
  • step S9 The power P2 when this delay amount ⁇ is reduced by ⁇ ⁇ 2 and the initial power P1 are compared (step S9).
  • step S9 if P2 ⁇ P1 (Yes in step S9), as the direct path from the local oscillation circuit 11 to the demodulation circuit 14b becomes smaller, its difference from the path of the leakage component 15 through the duplexer 13 becomes smaller, showing that the noise level decreases. This corresponds to the direction II of control in Fig. 13B described above.
  • step S10 P1 is substituted by P2 (step S10) and, returning to step S7, the delay amount is further reduced by ⁇ ⁇ 2, and the processing of step S7 and the subsequent steps is continued with.
  • Fig. 14 is a view given in further explanation of the path time difference and the noise level' (relative value) illustrated in Fig. 7; since the I channel and the Q channel have a 90 ° phase difference, if optimization is effected in respect of one channel, the noise level of the other channel becomes larger.
  • Fig. 15 is a graph in which the path time difference and the noise level (relative value) are found in respect of the sum (I 2 +Q 2 ) of the noise of the I and Q channels.
  • the path time difference is 0.5 (path difference ⁇ /2)
  • an improvement in the noise level of 10 dB can be achieved by correcting the path time difference to 0.2 (path difference ⁇ /5) by controlling the amount of delay of the delay circuit 18 (see Fig. 15, II ⁇ I).
  • Fig. 16 is a view showing a further embodiment of the present invention.
  • a characteristic feature of this embodiment is that a delay circuit 20 is provided between the duplexer 13 and the power feed terminal of the antenna 16.
  • the port allocation of the duplexer is such that the TX terminal communicates with the ANT terminal i.e. TX terminal ⁇ ANT terminal, but the TX terminal ⁇ RX terminal is blocked, and coupling is effected from the ANT terminal ⁇ RX terminal.
  • the delay circuit 20 comprises a delay line DL of line length 1 arranged between the duplexer 13 and the antenna (load Z L in the Figure).
  • the line length 1 between the antenna 16 and the duplexer 13 can be adjusted by means of this delay line DL.
  • antenna load impedance Z L is as follows.
  • Z Z 0 Z L cos ⁇ l + Z 0 sin ⁇ l Z 0 cos ⁇ l + Z L sin ⁇ l
  • Fig. 18 is a graph showing the relationship between the impedance Z of the antenna seen from the duplexer in Fig. 17 and line length 1.
  • the amount of the leakage of the transmission signal changes depending on the antenna impedance Z. Consequently, the amount of leakage can be controlled by adjusting the line length 1 to the power feed terminal by means for example of a delay line DL inserted as a delay circuit 20.
  • the degree of coupling of the duplexer 13 (transmission (TX) terminal ⁇ reception (RX) terminal) therefore theoretically becomes infinitely small (0) if the antenna terminal impedance coincides with the characteristic impedance Z 0 .
  • the limit is about - 40 dB.
  • the amount of the leakage of the transmission signal to the demodulation circuit can be reduced by providing a delay circuit 20 and adjusting the line length of the delay circuit 20 so as to make the impedance Z of the antenna seen from the duplexer approach more closely to the characteristic impedance.
  • a delay circuit 20 is provided between the transceiving antenna 16 and duplexer 13 in Fig. 16 can also be applied in the embodiments of Fig. 5, Fig. 8 and Fig. 9 described above.
  • Fig. 19 is an example extending the embodiment of Fig. 16.
  • connection is changed over between a plurality of antennas 16a to 16d using a switch 21.
  • delay circuits 22a to 22d are inserted between the switch 21 and the antennas 16a to 16d.
  • the leakage of the transmission signal to the demodulation circuit 14b can be minimized by making the corresponding antenna terminal impedance approach the characteristic impedance by adjusting the line lengths in the respective delay circuits 22a to 22d.
  • an RFID transceiver device is provided that is capable of high sensitivity reception, by the reduction of noise, irrespective of the distance to the tag. This makes it possible to configure an RFID system of high reliability.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Artificial Intelligence (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Near-Field Transmission Systems (AREA)
  • Transceivers (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
EP05255049A 2005-04-08 2005-08-16 RFID Sende-Empfangsgerät Active EP1710727B1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2005111531A JP4387323B2 (ja) 2005-04-08 2005-04-08 Ｒｆｉｄ用送受信装置

Publications (2)

Publication Number Publication Date
EP1710727A1 true EP1710727A1 (de) 2006-10-11
EP1710727B1 EP1710727B1 (de) 2009-06-17

Family

ID=36675932

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05255049A Active EP1710727B1 (de) 2005-04-08 2005-08-16 RFID Sende-Empfangsgerät

Country Status (7)

Country Link
US (1) US7492812B2 (de)
EP (1) EP1710727B1 (de)
JP (1) JP4387323B2 (de)
KR (1) KR100731227B1 (de)
CN (1) CN1845469B (de)
DE (1) DE602005014938D1 (de)
TW (1) TWI279992B (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1939787A2 (de) * 2006-12-29 2008-07-02 Samsung Electronics Co., Ltd. Vorrichtung und Verfahren zur Verbesserung der Empfangsempfindlichket in einem tragbaren RFID Geräten
US7492812B2 (en) * 2005-04-08 2009-02-17 Fujitsu Limited RFID transceiver device

Families Citing this family (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7327802B2 (en) * 2004-03-19 2008-02-05 Sirit Technologies Inc. Method and apparatus for canceling the transmitted signal in a homodyne duplex transceiver
US7545272B2 (en) 2005-02-08 2009-06-09 Therasense, Inc. RF tag on test strips, test strip vials and boxes
US8226003B2 (en) 2006-04-27 2012-07-24 Sirit Inc. Adjusting parameters associated with leakage signals
KR100716018B1 (ko) * 2006-05-17 2007-05-08 한국과학기술원 모바일 무선인식 리더기 및 그 출력 누설신호 제거방법
KR101184702B1 (ko) * 2006-09-21 2012-09-20 삼성전자주식회사 ｍＲＦＩＤ 리더기
KR100819045B1 (ko) * 2006-11-08 2008-04-02 한국전자통신연구원 Ｒｆｉｄ 리더기의 출력 최적화 장치 및 방법
KR100789369B1 (ko) 2006-11-14 2007-12-28 한국전자통신연구원 누설 송신신호의 방지를 위한 ｒｆｉｄ 리더
KR101372060B1 (ko) * 2007-01-30 2014-03-07 엘지이노텍 주식회사 변조주파수 다중화를 이용한 ｒｆｉｄ 수신 시스템
US8855029B2 (en) * 2007-03-21 2014-10-07 Skyworks Solutions, Inc. LMS adaptive filter for digital cancellation of second order inter-modulation due to transmitter leakage
EP2127100A4 (de) * 2007-03-21 2012-07-25 Skyworks Solutions Inc Lms-adaptives filter für digitale unterdrückung von intermodulationen zweiter ordnung aufgrund von senderleckage
US8248212B2 (en) 2007-05-24 2012-08-21 Sirit Inc. Pipelining processes in a RF reader
JP5060193B2 (ja) * 2007-07-18 2012-10-31 京セラドキュメントソリューションズ株式会社 データ送受信装置及び画像形成装置
KR100932064B1 (ko) * 2007-09-04 2009-12-15 한국전자통신연구원 Ｒｆｉｄ 태그 및 그 제어 방법
US8427316B2 (en) 2008-03-20 2013-04-23 3M Innovative Properties Company Detecting tampered with radio frequency identification tags
US8446256B2 (en) * 2008-05-19 2013-05-21 Sirit Technologies Inc. Multiplexing radio frequency signals
EP2329429A4 (de) * 2008-09-17 2015-07-29 Semiconductor Energy Lab Halbleiterbauelement
US8760520B2 (en) * 2008-11-10 2014-06-24 Eduard Levin System and method for tracking and monitoring personnel and equipment
US8169312B2 (en) * 2009-01-09 2012-05-01 Sirit Inc. Determining speeds of radio frequency tags
US8036606B2 (en) * 2009-02-03 2011-10-11 Ubidyne, Inc. Method and apparatus for interference cancellation
US8421601B2 (en) * 2009-03-22 2013-04-16 International Business Machines Corporation Active/passive RFID transponder control function
US20100289623A1 (en) * 2009-05-13 2010-11-18 Roesner Bruce B Interrogating radio frequency identification (rfid) tags
US8416079B2 (en) * 2009-06-02 2013-04-09 3M Innovative Properties Company Switching radio frequency identification (RFID) tags
US20110205025A1 (en) * 2010-02-23 2011-08-25 Sirit Technologies Inc. Converting between different radio frequencies
CN101794370B (zh) * 2010-04-09 2012-01-11 深圳市远望谷信息技术股份有限公司 射频识别读写器接收机灵敏度远程测试方法和装置
KR20110124042A (ko) * 2010-05-10 2011-11-16 삼성테크윈 주식회사 위상 노이즈가 제거되는 알에프아이디(ｒｆｉｄ)의 리더
JP5857343B2 (ja) * 2010-07-07 2016-02-10 オプテックス株式会社 受動型赤外線検知センサ
JP5633270B2 (ja) * 2010-09-16 2014-12-03 株式会社リコー 送受信装置
CN102148724B (zh) * 2011-01-31 2014-12-31 中兴通讯股份有限公司 链路检测方法及网络接入设备
US10062025B2 (en) 2012-03-09 2018-08-28 Neology, Inc. Switchable RFID tag
US8781049B1 (en) * 2012-12-27 2014-07-15 Intel Mobile Communications GmbH Signal delay estimator with absolute delay amount and direction estimation
CN104883199A (zh) * 2015-05-12 2015-09-02 惠州Tcl移动通信有限公司 一种无线终端及其数据接收、发送方法
CN106815625B (zh) * 2015-12-02 2020-03-20 四川华大恒芯科技有限公司 一种适合超低功耗设计的解调电路
US20170302429A1 (en) * 2016-04-15 2017-10-19 Andrew Wireless Systems Gmbh Duplexing and combining networks
CN107359947B (zh) * 2016-11-07 2020-09-15 天地融科技股份有限公司 电路延时自检测装置和系统
US20220360362A1 (en) * 2021-05-06 2022-11-10 Apple Inc. Systems and methods for high power operation in user equipment

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0531125A2 (de) 1991-09-04 1993-03-10 Nec Corporation Funksendeempfänger
GB2300318A (en) 1981-02-10 1996-10-30 Plessey Co Ltd Improvements in or relating to transceivers
US6229992B1 (en) * 1994-11-15 2001-05-08 University Of Bristol Full-duplex radio transmitter/receiver
US6311045B1 (en) * 1997-07-28 2001-10-30 Roke Manor Research Limited Apparatus for signal isolation in a radio transmitter-receiver
US6393259B1 (en) * 1998-03-10 2002-05-21 Sony Corporation Amplifier circuit and transceiver
EP1211630A2 (de) 2000-11-29 2002-06-05 Kipp, Ludwig RFID Kommunikationsverfahren, System und Transponder
JP2003174388A (ja) 2001-12-06 2003-06-20 Hitachi Kokusai Electric Inc 質問器の復調回路

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08122429A (ja) * 1994-10-25 1996-05-17 Sumitomo Electric Ind Ltd 移動体識別装置の干渉補償装置
JPH0969799A (ja) * 1995-09-01 1997-03-11 Antenna Giken Kk 自動制御サーキュレータ装置
JP3670454B2 (ja) * 1997-08-28 2005-07-13 株式会社日立国際電気 非接触ｉｃカードシステム
JPH11331897A (ja) * 1998-05-19 1999-11-30 Nec Shizuoka Ltd 通報保留機能付き無線選択呼出受信機および無線選択呼出受信方法
DE69921658T2 (de) * 1998-07-24 2005-10-20 Checkpoint Systems, Inc. Optisches Interface zwischen Empfänger und Auswerteeinheit für Antwortsignale eines Etiketts in RFID-Systemen zur Erkennung von leistungsschwachen Resonanzetiketten
ATE311039T1 (de) * 2000-06-28 2005-12-15 Thomson Licensing Hochfrequenz-oszillator
US6686830B1 (en) 2000-06-28 2004-02-03 Applied Wireless Identifications Group Homodyne I/Q transceiver for a spread spectrum reader
US6567649B2 (en) * 2000-08-22 2003-05-20 Novatel Wireless, Inc. Method and apparatus for transmitter noise cancellation in an RF communications system
US7330500B2 (en) * 2001-12-07 2008-02-12 Socovar S.E.C. Adjustable electronic duplexer
KR20050011046A (ko) * 2003-07-21 2005-01-29 (주)텔리뷰 주파수 시프터를 이용한 직접 변환 복조방법 및 복조장치
JP4387323B2 (ja) * 2005-04-08 2009-12-16 富士通株式会社 Ｒｆｉｄ用送受信装置

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2300318A (en) 1981-02-10 1996-10-30 Plessey Co Ltd Improvements in or relating to transceivers
EP0531125A2 (de) 1991-09-04 1993-03-10 Nec Corporation Funksendeempfänger
US6229992B1 (en) * 1994-11-15 2001-05-08 University Of Bristol Full-duplex radio transmitter/receiver
US6311045B1 (en) * 1997-07-28 2001-10-30 Roke Manor Research Limited Apparatus for signal isolation in a radio transmitter-receiver
US6393259B1 (en) * 1998-03-10 2002-05-21 Sony Corporation Amplifier circuit and transceiver
EP1211630A2 (de) 2000-11-29 2002-06-05 Kipp, Ludwig RFID Kommunikationsverfahren, System und Transponder
JP2003174388A (ja) 2001-12-06 2003-06-20 Hitachi Kokusai Electric Inc 質問器の復調回路

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7492812B2 (en) * 2005-04-08 2009-02-17 Fujitsu Limited RFID transceiver device
EP1939787A2 (de) * 2006-12-29 2008-07-02 Samsung Electronics Co., Ltd. Vorrichtung und Verfahren zur Verbesserung der Empfangsempfindlichket in einem tragbaren RFID Geräten
EP1939787A3 (de) * 2006-12-29 2011-05-04 Samsung Electronics Co., Ltd. Vorrichtung und Verfahren zur Verbesserung der Empfangsempfindlichket in einem tragbaren RFID Geräten

Also Published As

Publication number Publication date
KR20060106588A (ko) 2006-10-12
TWI279992B (en) 2007-04-21
JP2006295419A (ja) 2006-10-26
EP1710727B1 (de) 2009-06-17
TW200637203A (en) 2006-10-16
KR100731227B1 (ko) 2007-06-22
CN1845469B (zh) 2010-05-05
US7492812B2 (en) 2009-02-17
US20060229032A1 (en) 2006-10-12
DE602005014938D1 (de) 2009-07-30
JP4387323B2 (ja) 2009-12-16
CN1845469A (zh) 2006-10-11

Similar Documents

Publication Publication Date Title
EP1710727B1 (de) RFID Sende-Empfangsgerät
US7369811B2 (en) System and method for sensitivity optimization of RF receiver using adaptive nulling
US7120394B2 (en) Front-end module and communication terminal
JP4524674B2 (ja) 無線タグ通信システムの質問器
US9154177B2 (en) Method for controlling transmission/reception timing of base station antenna for TDD wireless communications and base station antenna using the same
EP1722314A1 (de) RFID-Empfänger zum Beseitigen von Lecksignalen
US20040014449A1 (en) Radio interference suppression circuit and method, antenna multiplexer, transceiver circuit, and communication apparatus
US8410905B2 (en) RFID reader cancelling leakage signal
MXPA97006076A (en) Autoverification transceiver
CN102291156A (zh) 减少共用天线带内干扰的系统和方法
US5913154A (en) VSWR control technique for terminal products with linear modulation
JP4516029B2 (ja) リーダライタ装置
US20040264392A1 (en) Time division multiplexing connection transceiver and its receiving automatic gain control method
JP3309904B2 (ja) 無線用送受信機
JP2000091943A (ja) 無線通信装置
EP2266072B1 (de) Verfahren zum verringern eines rauschens in einem signal, das in einem kontaktloskarten-interrogator empfangen wird, und schaltung zum ausführen des verfahrens
KR100695398B1 (ko) 시분할 듀플렉싱 방식 무선 전송장치의 무선단 유닛
JP3898714B2 (ja) 無線装置
US10103706B2 (en) Transmission and reception device
US9184717B2 (en) Power control device
CN108418601B (zh) 一种载波对消系统
US20080076360A1 (en) Apparatus for combining two radios on a single antenna
KR20200073136A (ko) 누설 전력 저감을 위한 송수신기
KR101417035B1 (ko) Ｒｆ 송수신 장치
Nightingale et al. RF interference cancellation–a key technology to support an integrated communications environment

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA HR MK YU

17P Request for examination filed

Effective date: 20070410

17Q First examination report despatched

Effective date: 20070510

AKX Designation fees paid

Designated state(s): DE FR GB

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: FUJITSU FRONTECH LIMITED

Owner name: FUJITSU LIMITED

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 602005014938

Country of ref document: DE

Date of ref document: 20090730

Kind code of ref document: P

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20100318

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 12

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 13

REG Reference to a national code

Ref country code: DE

Ref legal event code: R082

Ref document number: 602005014938

Country of ref document: DE

Representative=s name: REICHERT & LINDNER PARTNERSCHAFT PATENTANWAELT, DE

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 14

Ref country code: DE

Ref legal event code: R081

Ref document number: 602005014938

Country of ref document: DE

Owner name: FUJITSU FRONTECH LTD., INAGI, JP

Free format text: FORMER OWNERS: FUJITSU LIMITED, KAWASAKI-SHI, KANAGAWA, JP; FUJITSU FRONTECH LTD., INAGI, TOKIO/TOKYO, JP

REG Reference to a national code

Ref country code: GB

Ref legal event code: 732E

Free format text: REGISTERED BETWEEN 20181108 AND 20181114

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20230703

Year of fee payment: 19

Ref country code: DE

Payment date: 20230627

Year of fee payment: 19

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20240627

Year of fee payment: 20